'The Simpsons' -- Accused of Mob Hit ... Yous Guys Stole My Identity

"The Simpsons" pulled off a major heist when the mafioso character Louie rolled into Springfield -- and now a "Goodfellas" star wants a cut of the action.

Frank Sivero played Frankie Carbone in the classic 1990 film ... and says "The Simpsons" created a Carbone copy of that character when Louie first appeared in an episode entitled "Bart the Murderer" on Oct. 10, 1991.

Louie, who is Fat Tony's henchman on "The Simpsons" ... is hardly a regular. According to Sivero's lawsuit against FOX, the character appeared in 15 more episodes between his debut and April 27, 2014.

In the suit, obtained by TMZ, Sivero says he lived in the same apartment complex as some of the 'Simpsons' writers back in '89 ... and they knew all about the character he "created and developed" for 'Goodfellas.'

To the naked eye ... Louie does look like a dead ringer for Frankie.